Oftentimes, there is a desire to illuminate a compartment space when a compartment door is opened. Examples of compartments benefiting from illumination include automobile or boat storage consoles, cabinetry, security safes, lockers, the inside of a refrigerator, closets, and the like. While some such compartments are wired with electricity, many such compartments are not wired for electricity and it can be a costly process to connect these compartments to a plentiful power source such as an AC mains, a car battery or the like, which will typically involve drilling, wiring, and housing power adapter electronics.
A popular alternative to wired illumination of compartments is the use of battery powered light sources, especially battery powered light emitting diode (LED) light sources which can run for several hours before changing batteries. In a common form, these light sources have a push button for toggling the lights on and off. Whereas these light sources save the cost and effort of running wires and power conversion hardware from a plentiful supply, users can easily forget to turn off the lights when they no longer require illumination resulting in needing to frequently replace batteries that have lost their charge as a result of the lights being left on.
Improvements on the simple toggle switch have included the use of turn-off timers that automatically shut off the LEDs a predetermined time after the user has switched it on. These timers are often set for one particular time duration which may or may not be appropriate for how the user is interacting with the compartment. They also require the user to manipulate a toggle switch to turn the light on which can be inconvenient when one's hands are full, for example.
Toggle switches have also been tethered to wire harnesses and installed against the compartment door such that the door itself actuates the switch when closed to turn off the light, and actuates the switch when open to turn on the light. This method, while promoting efficient use of the battery, requires the additional cost of cabling and a remote door switch, and takes extra time to install within the compartment. Tethered switches further require that the LED module cannot be easily removed from the compartment and used as a fully portable light source if desired.
Additional improvements have included the use of proximity sensors employing passive infrared (IR) sensors to sense motion to trigger the LED source on. A lack of motion prompts the LED source to turn off. This solution results in far less wasted power from the batteries by ensuring the compartment is lit only while the user is interacting with it. Proximity sensors, however, have the disadvantage of requiring special placement within the compartment to detect motion which may be different than the location for optimal illumination, may require the use of a lens design that is typically separate from the primary light source lens, and may result in a higher product cost. In some designs, proximity sensors are mounted remotely from the light source complicating the installation and further increasing the product cost.
Another class of available LED products combine LED light sources with ambient light sensors for the purpose of turning on the LEDs in the dark. This technique is commonly employed in outdoor landscape lighting and nightlights. These devices, like those taught by Leen in U.S. Pat. No. 6,709,126, place the ambient light sensors away from the LED light source such that the LED light source does not impact the detected ambient light measurement. This class of product would not be suitable for compartment lighting as the triggering sensor would likely be always lit if placed in a closed compartment, unnecessarily wasting battery power.